The present invention relates to catalyst structures for the production of nitric acid and hydrocyanic acid, to metal fibers based on noble metals and suitable for the production of catalysts, to netting and non-wovens made therefrom, and to processes for the production of such fibers, non-wovens and nettings.
German Patent DE 199 45 742 C1 discloses a metal fiber catalyst body, the metal fibers of which are produced by melt extraction. Using textile techniques, non-woven fabrics, among others, are produced from the fibers. The catalyst material platinum, palladium rhodium is contained in the fibers or present in the woven material as additional fibers.
German published patent application DE 100 00 097 A1 discloses melt extraction processes for metal fiber production from thin fibers with diameters of less than 100 μm using melt bath temperatures of up to above 1500° C.
German published patent application DE 197 12 625 A1 describes a process in which metallic fibers, among others, are deposited through the meshes of a distributing roller onto a moving substrate and joined together at intersection points.
These processes seem to be unsuitable or at least difficult to implement for the production of metal fibers and nettings or non-wovens produced therefrom in the case of metals with a high melting point.
German Patent DE 100 40 591 C1 teaches the method of alloying platinum, iridium, rhodium and ruthenium, among others, with boron and phosphorus.
The efficiency of known catalysts, in particular platinum-rhodium catalysts, decreases over time.